CARDIOSELECTIVE ~-BLOCKERS ARE SAFER FOR DIABETIC PATIENTS

It has been suggested that non-selective ~-adrenoceptor blocking drugs are contraindicated in diabetic patients liable to

hypoglycaemic attacks for a number of reasons. As the more cardioselective (~1) blockers are less likely to cause these complications, they should be safer in diabetic patients.

• Non-selective ~-blockers such as propranolol potentiate insulin hypoglycaemia and delay recovery of blood glucose levels. Of the available cardioselective ~-blockers, atenolol and acebutolol have some advantages but opinions are divided on metoprolol.

• Cardioselectivity may also influence the way in which ~-blockers alter the metabolic response to hypoglycaemia, atenolol seeming to have less effect than acebutolol and propranolol.

• The symptoms of hypoglycaemia are affected in a similar way by cardioselective and non-selective ~-blockade. Both may therefore 'mask' hypoglycaemia.

• Cardioselectivity changes the effect of the cardiovascular response to hypoglycaemia. Non-selective ~-blockade causes a ri in systolic and diastolic SP and reflex bradycardia, while with selective blockade there is a smaller rise in systolic and a fali in diastolic oressure and a slif!ht rise in pulse rate.

• Aggravation of vascular insufficiency, leading to gangrene, is less likely with cardibselective compounds.

"n conclusion. ~-blockers can be used in diabetics when they are indicated ... The cardioselective ~-blockers however, should be used as they are less likely to ag­gravate hypoglycaemia. precipitate hypertensive crises during hypoglycaemia and compromise peripheral circulation. It remains to be seen whether dosage of insulin or oral hypoglycaemic drugs needs to be modified when cardioselective~· blockers are given concomitantly.'

Waal-Manning. H.J.: Drugs 17: 157 (Mar 1979)

4 INPHARMA 31 Mar 1979 0156-2703/79/0331-0004 $00.50/0 © ADIS Press